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H. c. WENDT 2,73 L83 SYMMETRICAL GYROSCOPE Filed Dec. l2, 1952 3 Sheets-Sheet l *li wf Jan. 24, E356 H. c. WENDT SYMMETRICAL GYRoscoPE 3 Sheets-Sheet 2 Filed DBC. 12, 1952 lll."

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Inventor: bia-WH C. Wendt? H. c. WENDT 2,733,836 SYMMETRICAL GYROSCOPE Filed Dec. l2, 1952 3 Sheets-Sheet 3 www United States Patent O 2,731,836 SYMMETRICAL GYROSCOPE Harry C. Wendt, Saugus, Mass., assigner to General Electric Company, a corporation of New York Application December 12, 1952, Serial No. 325,577 18 Claims. (Cl. I4-5.7)

The present invention relates to gyroscopes, and more particularly to the construction of gyroscopes having novel and improved gyro rotor structures.

In the heretofore conventional gyroscope, the rapidly tends to preserve an alignment 1n space by virtue of the gyroscopic inertia developed with high-speed rotation of the relatively heavy rotor. Those versed in the art appreciate that the errors and of much improved performance of massproduced gyroscopes on that basis alone. Also, when reductions are made in the Weight of the gyro rotor, to lessen the load upon rotor and gimbal bearings, and thus to decrease friction, there are According to the instant invention, the foregoing dis advantages are very greatly minimized in a most simple struction preferably employs the electrical be developed. As a result of the complete symmetry obtained by the present teaching, windage forces, and dimensional changes in the rotor structure with temperature variations, are substantially ineffective to occasion unbalancing. Further, greater gyroscopic inertias are inherently obtainable with the gyro rotor of 'this invention than with yrotors of 2,731,836 Patented Jan. 24, 1956 structures of the same small size. As will appear more fully hereinafter, simple, highly accurate, and rugged constructional features are also present.

Accordingly, it s one of the objects of the instant invention to provide a gyroscope having a novel and improved rotor structure.

Second, it is an object a rotor structure with an inertia to weight.

Further, an object of this invention is to provide a gyroscope wherein the need for a conventional rotor gimbal is obviated.

Further, it is an object to provide a gyroscope having a symmetrical rotor structure which preserves balance despite temperature-induced dimensional variations and changes in windage forces.

Additionally, it is an object to provide a high-accuracy gyroscope having a simple and rugged rotor structure of to provide a gyroscope having improved ratio of gyroscopic leads running through these trunnions.

Although the features of this invention which are believed to be Fig. 2 iS tion of a rotor structuresuch as that of Fig. 1;

Fig. 3 is a partly cut-away view of a rotor structure such as that shown in Figs. l and 2;

Fig. 4 illustrates a directional gyroscope of the invention;

Fig. 5 depicts a tion;

Fig. 6 represents a unique gyro suspension and rotor structure construction;

Fig. 7 is a single-axis gyroscope embodiment; and

Fig. 8 discloses an enclosed gyro rotor structure assembled in accordance with this invention.

Referring to the pictorial representation of one of my arrangement gyro vertical arrangement of the invengyro rotor structures, in Fig. l, it should be observed that the rotor comprises two collinear spaced-apart rotor halves, 1 and 2, of like dimensions and configurations, which are rapidly spun in the same angular direction around the spin axis 3 3 by motive means not illustrated. The ends of rotor shaft 4, to which the rotor halves are attached, are visible in this drawing. Rotor shaft 4 is rotatable in bearings supported by the thin flat bar or plate 5 positioned between and separated from the oppositely-disposed rotor halves. Trunnions 6 on each side of the bar 5 permit a rotatable mounting 0f the entire rotor structure about the axis 7-7 perpendicular to the spin axis 3-3.

It is important to note that, as distinguished from the conventional gyroscope, therotor structure gimbal or frame has been eliminated in the foregoing assembly and complete mechanical symmetry has been obtained. In accordance with heretofore customary practice, the gyro rotor or gyro rotors have been mounted for rotation about the spin axis on a shaft supported in an outer frame or gimbal entirely encircling the rotor. That rotor frame or gimbal has always necessarily been of a relatively massive and heavy construction to withstand the loads impressed upon it by the gyroscope, to resist dimensional variations with temperature, to preserve an accurate alignment of the minor axis pivots, and to maintain a fixed position of the rotor shaft. The conventional rotor frame or gimbal not only has undesired weight, from the standpoint of detrimentally increased loading of support bearings and attending increased bearing frictions, but this dead Weight has also been distributed beyond the outer surfaces of the rotor, where its adverse inertia effects are most strongly exerted and most destructive of gyro ac curacy. Further, assembly of the rotor structure has been a complicated process due to the difficulties of accurately fitting the rotor and motive means within the frame, and the minor axis pivots into the frame. 1t is obvious, too, that the space consumed by the rotor gimbal has either limited the size which the gyro rotor may assume in a gyroscope of any given outer dimensions, or has increased the outer dimensions of a gyroscope beyond what they would be in a unit not requiring a rotor girnbal.

By way of contrast with prior gyro rotor structures having the preceding disadvantages and limitations, the arrangement of Fig. l is found to possess no surrounding gimbal or frame. Pivotal support of the rotor structure is achieved through a dat plate or bar S which mounts the rotor shaft 4 for its rotation about the spin axis. Plate 5 is preferably of rectangular outer configuration, though not necessarily, and may be made light in weight, extremely rigid, insensitive to unbalance by temperatureinduced dimensional changes or by changes in windage effects, very simple to fabricate, and small in size. The inherent rigid property of a bar or plate such as that illustrated as 5 in the drawings affords a far more stable support for the rotor structure and a more accurate alignment of pivots 6 than could be achieved with the usual ring or hollow frame type of support. In addition to being small, the dead weight of the support 5 is concentrated near the innermost portions of the gyroscope where its inertia is rendered of the least possible effect. With a support bar or plate 5 dimensioned as illustrated, only the small trunnions of the supporting element extend beyond the greatest radius of the rotor, and the overall size of the entire rotor structure is, accordingly, at an absolute minimum.

Greater detail of a preferred structure, such as that of Fig. l, is revealed in Figs. 2 and 3, wherein the former depicts certain parts in an exploded relationship, and wherein the latter shows an oblique view of the assembled structure with one-quarter cut away to expose the interior. For convenience and simplicity of description, those portions of the structure of Figs. 2 and 3 which are substantially the same as those of Fig. 1 are identified by like reference characters. Each of the identical rotor halves 1 and 2 is preferably fabricated of two parts: one of which, 8 in the case of rotor half 1, and 9 in the case of rotor half 2, is an annular member of a weighty material suitable for producing a large gyro inertia, such as a tungsten alloy, shrunk onto a relatively light-weight umbrella-shaped element, 10 in the case of rotor half 1, and 11 in the case of rotor half 2. This construction, which is a preferred one though not essential, affords a desirably high ratio of inertia to weight for the rotor structure, thereby minimizing the bearing friction in the gyro support. Rotor elements 10 and 11 may be cooled through vent holes, such as 12 on element 11, and may be further reduced in weight while preserving the rugged strength by the formation of holes 13 and 14, respectively.

Support bar 5 is shown to have two openings 15, therein, this construction being advantageous not only in accomplishing a further reduction of unwanted weight and inertia, but also in permitting electrical connections to be brought to two of the electrical power leads 1.6, which are concentric with trunnions 6 and insulated therefrom. Bar 5 provides a support for the rotor halves 1 and 2 which are coupled for rotation with the spin axis shaft 4. A central hollow cylindrical spacer 17 on shaft 4 separates two inner-raceway bearing members 18 rmly attached to shaft 4, and bearing balls 19 enable a low-friction rotation of the rotor shaft in support 5 by rolling between the inner raceways 18 and the common stationary outer raceway 20 riveted to the support S. The motive means for the rotors comprises two hysteresis motors, one associated with each rotor half. Motor stators 21 and 22 for rotor halves 1 and 2, respectively, comprise stator lamination stacks 23 and 24 with stator windings 25 and 26 about these lamination stacks. Flanged tubular members 27 and 28, mounted upon the outer raceway 20, support stators 21 and 22, respectively, such that they are concentric with and spaced from the rotor shaft 4 and are suspended in the recesses or hollow interiors of rotor halves 1 and 2*. Annular rotor laminations 29 and 30 for the inside-outfhysteresis motor are rigidly held within the rotor elements 10 and 11, respectively, and impart the spin to the rotor halves.

Further advantages of my invention appear from the foregoing disclosures. One is the fact that the socalled figure of merit, that is, the ratio of gyro inertia to weight of the rotor structure, is much improved beyond those values obtainable with the usual rotor gimbal arrangement. Even with the support bar 5 cut away to have the illustrated openings, this support is of the utmost rigidity and simple machineability, and, since the thickness is very small, its mass shift by creepage is only a minute fraction of that which is present in the conventional large encompassing girnbal. rlhe construction is also of particular merit in that the rotors spin with a rotation of the inner raceway of the rotor shaft bearings. Motor bearing life is thus much improved over that of a bearing wherein the outer raceway revolves, the fatigue life of the latter bearing arrangement being only 1/3 and the lubrication life, due to the lubricants being thrown off the bearing balls, being only Vs of such lives in the improved arrangement in which the inner raceway rotates. Exact symmetry of my structure is also a most advantageous characteristic, inasmuch as temperature-responsive dimensional changes of parts of both halves of the structure are the same and no errors may be introduced by unbalance effects. The windage forces on both rotor halves being the same, balance is maintained so accurately that wind shrouds, normally essential in known gyros, need not be used.

it should be understood that the present rotor structure represents an unconventional and highly advantageous solution to the problem of vastly improving gyro accuracies without reducing the usefulv life of such instruments and without so complicating their manufacture that mass .production would be -physically impossible or economically impractical. Near-sonic flight speeds and above have imposed the most rigorous standards of acparted from level, but does not impose unbalanced torques curacies upon aircraft gyro instruments employed either when leveling is accomplished and the magnets spin 1n a as visual references or automatic control devices, besymmetrical relationship to the conducting ring Howcause even minute errors may result in large or disever, my rotor structure wherein the usual gimbal is elimiastrous deviations from a desired night path Addition- 5 nated is eminently suited for spinning magnetic material ally, 1n the case of directional gyroscopes, slaving of the in proximity with the conducting leveling ring without gyro with the eaiths magnetic iield becomes impossible requiiing extension of the rotor shaft through a gimbal during nights in polar regions, and it 1s essential that the or the positioning of magnetic materials beyond the outer gyro drift from a desired heading not exceed a few delimits of the rotor structure For this purpose, end porgrees per hour at most during those intervals when slaving tions 46 and 47, or merely one of these, are properly cannot be utilized Such factors as these have necessishaped and constiucted of material permanently magnetated development of gyroscopes having accuracies heretized in the prescribed manner, such as is set forth 1n tofore considered beyond realization through the applithe aforesaid patent. These end portions are part of the cation of known techniques. As was briefly stated earlier rotor structure itself, of course, and rotate accordingly herein, a larger useful gyro inertia may be produced con- Controlled precessions about the major axis 40-40 ventionally by increasiiie rotor speed which then raises may be accomplished by interaction between the magnetic windage errors and adversely increases rotor bearing fricfields produced by torque motor winding 49 and pertion to cause drift and to shorten bearing life or by marient magnets 5G mounted on the support bar 43 increasing the mass of the gyro rotor, which has the Magnetic fields established by the precession magnets 50 same attendant disadvantages as well as the further one and the precession coils 49 are in approximately a perof increasing friction in other support bearings the fricpendicular relation when the latter are energized, whereby tions of which contribute to gyro drift. Also, the weights a torque is exerted upon the rotor structure tending to and inertias oi parts not directly generating gyro inertia rotate it about the minor axis. In accordance with the may be reduced by employing lighter mateiials and smaller well known laws of gyroscopic precession this torque in dimensions, although such an approach inevitably leads turn causes precession of the gyro about the major axis, to weakened structure and misalignments of bearing pivin a direction dependent upon the direction of the precesots. Flotatiori or g'rnbals and rotor structure, and the sion coil flux and the direction of rotor rotation Prehighest precision manufacturing techniques, are further CeSSIOil in the desired Sense 1S achieved by appropriately possible avenues to decreased friction and greater gyro energizing coils 49, for example the energizing control accuracies, but only at the sacrifice of greater skill, time may be applied from a system slaving the gyro with a and expense. In accordance with the present invention magnetic COmPaSS 01 flUX Valve responsive to the earth`s however, this seeming impasse has been removed through magnetic ieldthe unique approach of constructing the rotor with two Normally, edging of the directional gyroscope about symmetrical halves, eliminating the rotor gimbal, and subthe minor axis is realized by engaging a shaped part stituting for the gimbal a pivotal support means interon the rotor frame or gimbal With a part Supported in mediate the rotor halves. the outer frame of the gyroscope. In one practice of ln its embodiment in a directional gyroscope as Shown this invention, with the usual rotor gimbal absent, the in Fig. 4, this rotor structure is particularly beneficial in Support bar 43 in Fig- 4 may itself cornprise one of additional respects, notably in affording improved levelthe edging elements By way of illustration, the main ing and caging. That instrument is illustrated as comgimbal 39 iS shoWn t0 be provided With Side ChannelS prising the usual outer housing 31 joined with a front 51 in Which d edging slide 52 inside the gimbal 39 may aange 32 containing a window 33 ihrounh which the dial be Siidably elevated t0 a Caged Position from a lower 34 may be viewed and compared with the index plate 35. position in Which lt rests upon a lowered edging yoke 53 Output shaft 36 actuates dial 34 in accordance with the pVoted on main gimbal gear 38 Cugln" slide 52 cnrrieS pivoted about the normally vertical maior axis 40`40 of the Slide, end Which, When 1t 1S fully elevated to the in the outer frame el. The rotor structure is pivotally caged Position, provides a Vertical tint edging Surface inlmounted in main gimbal 39 about the horizontal axis nledintely adjacent one Side of the dat Support ber 43- 42 which is perpendicular to both the normally horizontal 50 Dnshed lines 55 illustrute the Caged position of linger 54, Spin axis and the no1-malty vertical major axis 40. 40 and it is readily observed that bar 43 is then restrained As in the embodiment described previously, the rotor from PiVotal movement and is held in the desired caged strueture includes l rotor Support bal- 43 and two Symposition. This arrangement necessitates limited projec nietrical rotor halves, 44 and 45, which are caused to tion of the bar 43 outwardly beyond the lirnitS of rotor spin by motive means such as the hysteresis motors of halves 44 and 45- Figs. 2 and 3. For purposes of leveling the gyro rotor 5o Ceging finger sinlay have a channel formed therein t0 spin axis, that is, precessing the gyro rotor stiuctuie to a dVoid interference With rndgnetS 50, aS iS ShoWn- Alposition wherein the spin axis is normal to both the major though main gnnhul 39 is largely cut-away in the d1' 21W- and minor pivot axis, the arrangement employed is similar ing, it Will be appreclated that the mein body of Slide to that disclosed in Patent 2,585,693, issued February 52 iS on the inSide of the gimbal, that magnetS 50 are 12, 1952, and assigned to the same assignee as that of the nent in inward Poiition, and that the edging SurfaceS of present invention. The torques required for the leveling linger 54 bar 43 engage innerinoSt near the rotoi halVeS- procession are produced by the interreaction between per- @aging is initiated by Pressing knob 56 inwardly, Wheremarient magnet materials 46 and 47 rotating with 'the upon sliding rnernber 57, movable With the knob, preSSeS with the major gyro axis and symmetrically positioned 60 against the Circular Plate 60 which may be raised and in relation to the rotoi spin axis when the latter is level lowered relnnye to main gear 38 Elevation of Plate 50 Were a conventional rotor gimbal employed, the rotating also reSultS in raising of its attached pins 61, these in permanent magnets would have to be positioned outside turn pushing caging yoke 53 and its resiliently coupled the gimbal, with the rotor shaft extending through the cagi'ng slide 52 to the elevated caged position. Upon gimbal to impart the rotation, such that a maximum and release of knob S6, the sliding member 57 is immediundistorted magnetic tield from the magnets might interact ately drawn back by a spring not illustrated, and springs with the eddylcurrent nelds set up in the conducting ring. 62 and 63 quickly return the other parts to their un- As is well known, this interaction is eifective to precess caged positions. Figure 4 pictures an intermediate step the rotor structure to a leveled position when it has dein the ycaging process, with caging yoke 53, slide 52 and tinger S4 partly elevated. If preferred, the bar 43 may be shaped as a cam or have a projecting caging pin, and cooperate with appropriate caging mechanisms such as disclosed, for example, in the above-mentioned patent or in the copending application of Uses et al., Serial No. 272,614, tiled February 20, 1952, Patent No. 2,636,389, issued April 28, 1953, and also assigned to the same assignee.

Another embodiment of my invention is illustrated in Fig. 5, wherein there is shown a gyroscope having a normally vertical spin axis 6ft-64, such devices being identified in the art as gyro verticals, gyro horizons or artificial horizons. An outer casing 65 is attached to the usual front iiange 66, in which a partly spherical window 67 is positioned to permit observation of bank and dive-andclimb indications. Within the casing, bracket GS supports the yoke-shaped main gimbal 69 in bearings 70 for rotation about a normally horizontal major axis. The rotor structure of the gyroscope, which is substantially the same as those earlier described herein, is supported in main gimbal 69 about pivot axis 7l, this minor axis being perpendicular to the major axis and also normally horizontal. It will be observed that this rotor structure is substantially spherical, and that the intended configuration results from the substantially hemispherical contour of cach of the rotor halves 72 and 73, and the substantially circular shaping of the support plate 7 4. Ball or sphere type horizon or vertical gyroscopes have commonly been constructed with the rotor frame surrounded by a spherical or partly spherical indicator having graduated indicia thereon, and it has also been known to provide discontinuous indicia markings upon a member rotating with the gyro rotor, for the purposes and in the manner disclosed in my Patent No. 2,535,003, issued on December 19, 1950, and assigned to the same assignee as that of the present invention. By providing the rotor halves 72 and 73 with like hemispherical contours, their outer surfaces themselves constitute desired indicia-bearing surfaces of the instrument. Solid-line graduations 75, or discontinuousmarking graduations 76, or any combination of these applied to the surfaces register dive-and-climb indications when compared visually with a miniature airplane or other stationary index 77 mounted with the outer frame of the instrument. index 77 is shown to be adjustable with movements of its curved support 7S which is positioned, for example, by knob 79 through a rack and pinion structure not illustrated in full, the rack being formed upon the lower portion 80 of support 78 and the pinion being rotatable with knob 79. Circular support plate 74 may also carry one or more graduations. Or, plate 74 may mount one or two sets of ixed graduation members 81 and may also support the dive-and-climb angle figures which would not be readable if placed upon the spinning rotor halves themselves. in these instances, there is no need for graduations upon coloring ot' the rotor halves provides a desired background for the xed indicia, and discontinuous markings are desirable to evidence failure of rotor spin. In addition to aiiording improved markings, each of my rotor halves 72 and 73, or one of them alone, provide one cooperating element of the erecting system for the gyro vertical. For this purpose, the end portions 32 and 83 of rotor halves 72 and 73 arev made either of electrically conducting or permanent magnet material. The one of the end portions which is lowermost, such as 83 in Fig. 5 wherein the rotor structure is without gimbal stops and is universally free 6 in its suspension, cooperates with the erecting member 84 pendulously supported in the conventional two-degree-offreedom bail assembly comprising a first bail 85 pivoted about the major axis in bearings S6 and a second depending bail 87 pivoted in bail 85 about a second axis perpendicular to the major axis. Erecting member 84 is constructed ot conducting material if the rotor end portions 'are permanently magneti'zed, and, conversely, the member S4 is constructed of permanently magnetized the rotor halves, although 93 and 94 and about the minor axis material if the rotor end portions are selected to be of conducting material. With either structure, the eddy currents set up in the conducting material by the permanent magnet iields create fields which interact with the permanent magnet ields to exert torques tending to erect the rotor structure whenever it departs from the vertical. It should be apparent, therefore, that my invention is valuable in obviating the need for sphere-type indicators or backgrounds, or rotor spin indicators, or parts of the usual erecting system, or any grouping of these, in vertical spin axis gyroscopes. Control or remote indicator pickots 88 and 89 in Fig. 5, and 90 in Fig. 4, are representative of the conventional electrical devices which are customarily associated with such gyroscopic instruments.

It is not essential that the two rotor halves of my rotor structure be interconnected by a rotor shaft. Figure 6 depicts such rotor halves, 91 and 92, which rotate independently with rotor shafts 93 and 94, respectively, which are unconnected. Some variations in the speeds of the two rotor halves occasioned by the use of different motor units are not objectionable. Rotor half 92 has been shown in a sectional view to expose the shaft 94, its support bearings 9S, the motor stator 96 affixed to the stationary outer raceway and stator mounting 97, and the rotor laminations 98. Rotor half 91 is of like construction. Pivotal support of the rotor structure of Figure 6 is somewhat different from those supports considered earlier herein, inasmuch as there is no bar or plate which provides for the pivotal support. Instead, the 6-shaped main gimbal 98 has a through cross-member 99, rigidly fastened to or integral with the remainder of the gimbal, and that cross-member carries minor-axis bearing surfaces. Stator mountings 97 and 100 are pivotally supported upon cross-member 99 along minor axis 101-101 through bearings 102 which have their inner raceways attached to the cross-member 99. For ease of assembly, stator mountings 97 and l0() are preferably constructed of like halves which may be iixed together about the rotor shafts bearings 102, and the main gimbal cross-member 99 is likewise preferably made in two halves which may be fitted into each side of main gimbal 98 and joined in the middle between abutments which confine the inner raceways of minor axis bearings 102 to a centralized position. Slip rings or spirals, not shown, conduct current for the motor stators and may be conveniently located to communicate between the main gimbal 98 or cross-member 99 and the motor stators. Although Figure 6 illustrates the rotor spin axis in alignment with the major axis 10S- 103, this is simply to facilitate the representation of the structure, the normal position of the spin axis being perpendicular to the major axis. The embodiment in this igure, which may be either that of a directional, vertical or other type of gyroscope, accomplishes a4 further reduction of dead weight of the rotor structure and further concentrates weight of that type toward the center of the gyroscope, where its undesired inertia etects are minimized. The girnballess character of my rotor structure is particularly evident in this unit.

Features which render the instant invention important in the two axes of freedom gyroscope are present in the single axis or rate gyroscope pictured in Figure 7. As is well known, such instruments comprise a rotor structure, usually possessing the standard frame or gimbal, having its axis of spin perpendicular to the single support axis, about which latter axis there is resilient restraint to angular motion. Turning movements of the instrument about an axis perpendicular to the spin and support axes results in a precession about the support axis, the magnitudes and senses of angular deflections against the resilient restraint being proportional to the rates of such angular movements and in directions related to the directions of such movements. Accordingly, the rotor halves 104 and 105 in Figure 7 are adapted to spin with rotor shaft 106 75 about spin axis 107-107 perpendicular to the support axis 108 108, the shaft 109 for support about the latter axis being mounted in bearings 110 held in the outer casing 111 and the shaft 109 further being angularly restrained by spring 112 coupled thereto and with outer casing 1'11. Pick-off 113 translates angular deections of shaft 109 ture and its bracket are enclosed within a fluid-tight container 117 such that the buoyant effect of uid filling the spaces between the container 117 and outer casing 111 reduces the loading and friction of bearings 110 to a minute value. In an application of this nature, the circular support plate 114 is particularly well adapted to is hermetically sealed, or is surrounded in whole or part by a spherical-contour member carrying indicia thereon. Fig. 8 represents that arrangement, the rotor halves 121 and 122 being mounted fo rotation in th minor axes pivots 124 extending from diametrically opposite positions. Hemispherical 125 and 126 are supported one on each side of the suppo may carry indicia 127.

proved -gyroscopes in accordance with the teachings of the present invention.

the hysteresis motor described. Further, it is not essential that the motor be of the illustrated inside-out construction, but the rotor element of each ing directions about the mmor gyro axes.

It should thus be apparent that the specic embodiments of this invention disclosed herein are of a descripfiat plate means intermediate sald axis normal to said spin axis. gyroscopic device comprising a pair of collinear apart gyro rotors, and tiat plate means extending to said spin axis.

5. A gyroscopic device comprising two hollow cupshaped gyro rotors, means mounting said rotors for rotation about one spin axis in an axially-spaced relationship, said means arranged colnearly and carried by said coaxially with said spin axis, two rotors alixed to each of said mounting means annular electrical motor axis perpendicular to said spin axis.

6. A gyroscopic device as s et forth in claim 5 wherein across said pivotal supporting means through both of said lamination stacks.

8. A gyroscopic device comprising a pair of gyro rotors, means mounting said rotors for rotation about one spin axis in a close axially-spaced relation, and a tlat member of uniform thickness just short of the axial spacing be- 9. A gyroscopic device comprising a pair of gyro rotors, means mounting said rotors for rotation about one spin axis with a small axial spacing therebetween, and a single integral member extending fully across said rotors in said space between said rotors and normal to said spin axis, and pivotal support means supporting said member, said member constituting the sole support for said mounting means in said pivotal support means.

l` A gyroscopic device comprising a pair of gyro rotors, means mounting said rotors for rotation about one spin axis with a small axial spacing therebetween, a at member of uniform thickness just short of said spacing positioned between said rotors normal to said spin axis and extending fully across the space between said rotors, said member supporting said mounting means, and trunnions pivotally supporting said member about an axis normal to said spin axis, said member constituting the sole support for said mounting means in said trunnions.

1l. A gyroscopic device comprising an outer frame, a main gimbal pivotally mounted in said frame about a major axis, and a rotor structure pivotally mounted in said main gimbal about an axis normal to said major axis, said rotor structure comprising a support plate of uniform thickness extending substantially straight across said gmbal, pivot means mounting said plate in said gimbal about a minor axis normal to said major axis, a pair of gyro rotors, and means supported in said pivot means solely by said plate mounting said rotors on opposite sides of and close to said plate for rotation about a spin axis normal to said major and minor axes.,

12. A gyroscopic device as set forth in claim 1l wherein said rotors are substantially cup-shaped and are afiixed to a common rotor shaft, and further comprising, electrical motors for each of said rotors having two an nular stators mounted coaxially with said shaft in fixed relation to said plate and mounting means on opposite sides of said plate, and two annular hysteresis motor rotors each coupled with a diiferent one of said rotors and shaft for rotation therewith in surrounding relation to one of said annular stators, said stators and motor rotors being nested substantially within said cup-shaped gyro rotors. p

13. A gyroscopic device comprising a substantially straight and iiat rectangular member having uniform thickness, trunnions supporting said member for pivotal movement about a support axis symmetrical with said member and passing longitudinally through said member, a pair of substantially cup-shaped gyro rotors, bearing means mounting said rotors on said member for rotation on opposite sides of said member about a spin axis normal to said support axis, two annular electrical motor rotors coaxial with said spin axis one on each side of said member and each coupled to rotate one of said gyro rotors, and two annular electrical motor stators coaxial with said spin axis one iixedly mounted on each side of said member and positioned to rotate one of said motor rotors, said motor rotors and stators and said bearing means being nested substantially within the spaces existing between said cup-shaped rotors and said support member.

14. A gyroscopic device as set forth in claim 13 wherein said annular motor stators comprise two annular stator cores ixedly mounted on opposite sides of and adjacent said support member, and a single stator winding arrangement having substantially all the turns thereof linking both of said cores, whereby there are substantially no stator end turns next to said support member.

avancee 15. A gyroscopic device comprising an outer frame, a main gimbal pivotally mounted in said frame about a major axis, -a pair of gyro rotors, means mounting said rotors for rotation about one spin axis in an axiallyspaced relationship, support means extending between said rotors to support said mounting means for pivotal movement about a minor axis normal to both said spin and major axes, and erecting means supported independently of said rotors and mounting and support means and in proximity with at least one of the end portionsV of said rotors, said erecting means and at least one of said rotor end portions being one of conducting material and the other of material producing a magnetic field, whereby magnetic interaction therebetween precesses said rotors into alignment with said erecting means.

16. A gyroscopic device as set forth in claim 15 wherein said major and minor axes are normally horizontal, wherein said spin axis is normally vertical, and further comprising pendulous support means for said erecting means to cause precession of said rotors which coeces said spin axis into alignment with an average position of said erecting means.

17. A gyroscopic device comprising an outer frame, a main gimbal pivotaliy mounted in said frame about a normally horizontal major axis, a pair of substantially hemispherical gyro rotor halves, means mounting said rotor halves for rotation about one spin axis with a close co axial spacing to form a rotor structure having a substantially spherical exterior, and a substantially at circular support plate of uniform thickness just short of said spacing extending between said rotor halves to support said mounting means and rotor halves in said main gimbal for pivotal movement about a minor axis normal to both said spin and major axes, said plate being of the same diameter as said rotor halves to complete the substantially spherical exterior of said rotor structure.

, 18. A gyroscopic device comprising an outer frame, a main girnbal pivotally mounted in said frame about a normally horizontal major axis, a pair of substantially hemispherical gyro rotor halves, means mounting said rotor halves for rotation about a spin axis with a small axialpspacug therebetween to form a rotor structure having a substantially spherical exterior, indicia on the exteriors of said rotor halves, said indicia being arranged circularly about said rotor halves in planes normal to said spin axis, and substantially flat support means of uniform thickness just short of said spacing extending between said rotor halves to support said mounting means and rotor halves in said main gimbal for pivotal movement about a minor axis normal to both said spin and major axes.

' References Cited in the le of this patent UNITED STATES PATENTS 

